Typical portable computing devices include laptop and notebook computers and other portable computers. Unlike desktop computers, which must be constantly plugged into a wall outlet to receive power so that they can be used, portable computers include batteries so that users can use them while away from a wall outlet, such as on planes and trains, in conference rooms and so on. The batteries are rechargeable, so when they lose their power through usage of the portable computers, the computers can be plugged into a wall outlet to recharge their batteries.
Portable computers have become nearly as popular as desktop computers. The performance of portable computers has also increased to rival many desktop computers. The processing power of portable computers, their screen sizes, graphics chips, available memory, and available storage are nearly equal to that found in desktop computers. Indeed, one type of portable computer is known as the “desktop replacement,” which is intended to replace a typical desktop computer. Such portable computers usually include an optical drive, and can have a wide variety of peripherals attached to them.
Unfortunately, battery technology has not increased at the same pace as other technologies used in portable computers. Therefore, how long a portable computer can run on battery power is an issue that pervades design choices in which technologies to use in portable computers. Furthermore, users have become adept at monitoring power usage within portable computers. Users may have to adjust how they use their computers to ensure that the battery charge lasts as long as is needed.
Present battery management technologies are limited, however. Major components of a portable computer can individually perform power management. For example, the central processing unit (CPU) and the graphics processor of a portable computer may be able to have their operating frequencies reduced to limit power usage. Such individual power management is typically effective, however, only if the other components of a portable computer are also not consuming large amounts of power.
Other battery management technologies include reducing the backlight for the display of a portable computer based on the amount of power remaining in the battery. However, in all of these battery management technologies, power management is not based on the load of all the components of a portable computer as a whole. Therefore, while they are effective to some degree, they still do not optimally manage the remaining power of a battery within a portable computer.
One type of power management technique is particularly described in U.S. Pat. No. 6,289,399. In this patent, a computing device determines how the computer is currently being utilized by directly monitoring the load on the processor (i.e., the CPU), as well as the frequency of input/output (I/O) access, such as access to hard disk drives. Based on how the computer is currently being utilized, power can then be conserved appropriately. However, this approach has some disadvantages. First, it does not correctly determine how the computer is being used when there is a light load on the processor. Second, it does not correctly determine how the computer is being used when there is a load on another type of device that the user is currently using, such as a graphics or video chip, or memory. Third, if the sampling rate of monitoring the frequency of I/O access is too infrequent, then the approach may not correctly determine how the computer is currently being used. At the same time however, fourth, if the sampling rate of monitoring the frequency of I/O access is too frequent, then the approach itself may cause an undue load on resources of the computing device.
For these and other reasons, then, there is a need for the present invention.